Role of fluorescent microscopy in detecting Mycobacterium leprae in tissue sections

We compared the sensitivity of the fluorescent method with that of he modified Fite-Faraco method in the detection of Mycobacterium leprae in tissue sections. Fifty-six skin biopsies were obtained from patients having leprosy, particularly the paucibacillary type. Minor alterations were made in the deparaffinization and staining technique, as compared with Kuper and May's method, to obtain optimum fluorescence. Of 56 biopsies studied, 39 showed organisms by the fluorescent method and only 25 showed organisms by the modified Fite-Faraco method. The fluorescent method was found to be more advantageous than the modified Fite-Faraco method, particularly in paucibacillary cases. Fluorescent microscopy has the advantage of speed and ease of screening and reduces observer fatigue. Bacillary positivity rates were higher in the fluorescent method than in the modified Fite-Faraco method in each type of leprosy.